Coding and Decoding Questions

If 3#5 = -20, 1#4 = -30 and 6#5 = 10, then find the value of 4#9 = ?

In a certain code language, 'x' represents '+', '÷' represents 'x', '-' represents '÷' and '+' represents '-'. Find out the answer to the following question.

24 + 12 x 30 ÷ 2 - 6 = ?

If "#" means "subtraction", "&" means "division", "@" means "addition" and "%" means "multiplication", then 8442 & 9 # 7 % 6 @ 4 = ?

If '+' stands for multiplication, '-' stands for addition, 'x' stands for division, then what is the value of 128 + 9 - 16 x 4 = ?

If WASP STINGS HARD is coded as @%Z, HARD TO DEAL is coded as Z65 and HEAL LONG TIME is coded as 896, what is the code for HARD?

If '>' means 'minus', '<' means 'plus', '*' means 'multiplied by' and # means 'divided by', then what would be the value of

27 < 81 # 9 > 6 =

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?

12 x 6 ÷ 5 + 4 = ?

In a certain code, 'book is big' is written as 756; 'big is story' is 764 and 'story book is interesting' is 4356. Which digit represents 'interesting'?